Valve

ABSTRACT

A valve body ( 12 ) has an inlet opening ( 22 ) and an outlet opening ( 24 ) interconnected by a fluid passageway ( 28, 30 ) having a flow aperture ( 34 ). The valve comprises a diaphragm ( 14 ) (typically of the duckbill type) that is located across the flow aperture ( 34 ) and has slits in a collapsible aperture ( 39 ). This prevents backflow from the outlet to the inlet. The valve has an actuator ( 16 ) in the form of a plunger for influencing the fluid flow. Also disclosed is a pressure release valve whereby a high pressure on the outlet side can partially collapse the aperture ( 39 ) to temporality vent fluid from the high pressure outlet side.

FIELD OF THE INVENTION

The present invention relates generally to a valve and particularly,though not exclusively, to non-return valves and pressure relief valves.

BACKGROUND TO THE INVENTION

Non-return valves are common in industrial and domestic applications andare particularly prolific on pneumatic tyres. A conventional valvetypically comprises an inlet casing which is screw threaded within avalve stem of a tyre. The inlet casing houses a shaft along which avalve member slidably moves. The valve member is biased against a seatof the casing under the force of a compression spring so as to close thevalve. Such a conventional valve comprises a relatively large number ofcomponents, is relatively expensive and complicated in operation.

The applicant discloses in international patent application WO 00/77429a non-return valve which comprises a conical-shaped diaphragm in a fluidpassage way. The diaphragm has a collapsible aperture which has an apexthat is orientated in a forward flow direction. The diaphragm itselfinitiates closure of the collapsible aperture and the closure is furtherpromoted by fluid on the high pressure side of the valve to thus preventfluid flowing in a reverse direction. When pressure is applied to aninlet side of the diaphragm, the diaphragm deflects to expose theaperture and allow fluid to flow through the passageway from the inletto the outlet only.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided avalve comprising:

-   -   a valve body having an inlet opening and an outlet opening        interconnected by a fluid passageway having a flow aperture;    -   a diaphragm being constructed of a resiliently flexible material        and located across the flow aperture and including a collapsible        aperture which inhibits flow from the outlet to the inlet        openings via the flow aperture in a reverse flow direction and    -   a valve actuator for influencing the flow from the inlet to the        outlet.

In one embodiment of the present invention a valve seat is disposedabout the flow aperture and the valve actuator is at least in partmovably coupled to the valve body and arranged to operatively cooperatewith the valve seat to effect closure of the flow aperture to preventflow from the inlet to the outlet openings in a forward flow direction.

In this embodiment the valve actuator preferably comprises a plungertogether with a compression spring which urges the plunger into sealedabutment with the valve seat. The plunger may be elongate and configuredat one end to abut the valve diaphragm which is seated about the valveseat.

The valve actuator may also comprise a plunger guide tube in which theplunger is slidably housed for reciprocating movement. The actuatorpreferably also comprises a solenoid actuator which is located about theplunger guide tube and when electrically activated is designed to effectaxial movement of the plunger out of abutment with the valve seat topermit flow in the forward flow direction.

The diaphragm preferably is shaped about its periphery substantiallycomplementary to a recess formed in the valve seat to permit seating ofthe diaphragm relative to the valve seat. The diaphragm most preferablyis fixed or adhered to the valve seat. The diaphragm may also bedesigned to retrofit to a valve.

Preferably, the valve is a flow control valve.

In a second preferred embodiment of the present invention the valveactuator is connected to the diaphragm and is configured so that axialmovement of the actuator toward the fluid outlet deflects the diaphragmto expose the aperture and allow fluid to flow through the passagewayfrom the inlet to the outlet or the other way.

In this preferred embodiment the valve actuator may comprise an elongatemember formed integrally and generally coaxial with the valve diaphragm,which preferably is conically shaped. Alternatively, the valve actuatormay comprise an elongate member having at one end an engaging surfacebeing configured to abut the diaphragm at its inlet side. The valveactuator may also comprise a retaining element coupled to the elongatemember and configured to operatively engage the valve body to inhibitaxial displacement of the elongate member and its engaging surface andthus deflection of the diaphragm under pressure. In this embodiment thecollapsible aperture is in the form of one or more slits each beingformed through an axis of the valve and the valve diaphragm is formedintegrally with the valve body. The valve body preferably is configuredto retrofit to an existing valve stem. Alternatively the valve body maybe designed to be sealably inserted into a flow line. Preferably thefluid is water or compressed air.

According to a second aspect of the invention there is provided adiaphragm for a valve comprising a valve body having an inlet openingand an outlet opening interconnected by a flow passageway having a flowaperture, and a valve actuator at least in part being movably coupled tothe valve body to effect closure of the flow aperture to prevent flowfrom the inlet to the outlet openings in a forward flow direction, thediaphragm being located across the flow aperture and comprising acollapsible aperture which inhibits flow from the outlet to the inletopenings via the flow aperture in a reverse flow direction.

The diaphragm that forms a part of the valve according to the firstaspect of the invention and the diaphragm according to the second aspectpreferably are in the form of a generally conical-shaped diaphragmhaving the collapsible aperture located at or adjacent its apex which isorientated in the forward flow direction. The collapsible aperture mostpreferably is in the form of one or more slits each being formed throughan axis of the valve.

According to a third aspect of the invention there is provided apressure relief valve comprising:

-   -   a valve body including a fluid passageway which defines a fluid        inlet and a fluid outlet located on a low pressure and a high        pressure side of the valve respectively; and    -   a valve diaphragm in the form of a conical-shaped diaphragm        having a collapsible aperture located at or adjacent its apex,        said diaphragm being connected across the fluid passageway and        being constructed of a resiliently flexible material wherein the        diaphragm initiates closure of the collapsible aperture, the        diaphragm being configured whereby excessive pressure on the        high pressure side of the valve effects deflection of the        diaphragm to expose the collapsible aperture to temporarily vent        fluid from the high pressure side.

The collapsible aperture preferably is in the form of one or more slitseach being formed through an axis of the valve and its conical-shapeddiaphragm.

In one embodiment of the third aspect of the present invention the apexof the diaphragm is oriented in a forward flow direction and directedtoward the high pressure side of the valve. A person skilled in the artwill appreciate that a pressure release valve may not have a flow inforward direction. In a pressure release valve the forward direction isa direction that opposes a direction in which pressure may be released.

In an alternative embodiment of the fourth aspect of the presentinvention the apex of the diaphragm is which is oriented in a reverseflow direction and directed toward the low pressure side of the valve.

According to a fourth aspect of the invention there is provided a highpressure non-return valve comprising:

-   -   a valve body including a fluid passageway which defines a fluid        inlet and a fluid outlet located on a low pressure and a high        pressure side of the valve respectively;    -   a valve diaphragm being connected across the fluid passageway        and including a collapsible aperture, said diaphragm being        constructed of a resiliently flexible material and being        configured so that pressure imposed on the high pressure side of        the valve promotes closure of the collapsible aperture to        prevent fluid flowing in a reverse direction toward the inlet;        and    -   a reinforcing member being disposed across the valve body and        designed to operatively engage the diaphragm on its low pressure        side whereby the reinforcing member restricts deflection of the        diaphragm when a relatively high pressure is applied on the high        pressure side of the diaphragm thus maintaining closure of the        collapsible aperture and the valve.

In this aspect of the present invention the valve diaphragm ispreferably conical-shaped having its apex directed to the outlet and thehigh pressure side of the valve. The reinforcing member preferably alsois conical-shaped and configured to nest within the fluid passagewayadjacent the diaphragm on its inlet side. The reinforcing member maycomprise a plurality of fluid openings to permit the passage of fluid.

In all aspects of the present invention the diaphragm preferably isconstructed of a resiliently flexible polymeric material. The polymericmaterial most preferably is an elastomer such as a rubber material.Alternatively the polymeric material may be a nylon-based material. Thediaphragm of the valves of the first, third and fourth aspect of thepresent invention may also have a sealing function and may also be usedas a seal that may replace a conventional O-ring seal.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to achieve a better understanding of the nature of the presentinvention a preferred embodiment of a valve will now be described, byway of example only, with reference to the accompanying drawings inwhich:

FIGS. 1( a) and (b) are exploded and assembled view of part of a valveincorporating a non-return diaphragm;

FIGS. 2( a) to (e) are a plan and cross sectional views of the valvebody together with the diaphragm of the valve of FIG. 1;

FIGS. 3( a) to (f) are elevational and sectional views of the plungerand part of the valve body of the valve of FIG. 1;

FIGS. 4( a) to (c) are a detailed plan and sectional view of thediaphragm of the valve of FIG. 1;

FIGS. 5( a) to (f) are various elevational and plan views of the guidetube of the valve of FIG. 1;

FIGS. 6( a) to (f) are plan, elevational and sectional views of atraditional valve body which may be modified in accordance with that ofFIG. 2;

FIGS. 7( a) to (g) are elevational, plan and sectional views of atraditional plunger which is replaced with that of FIG. 3 in the valve;

FIGS. 8( a) to (e) are elevational, plan and sectional views of atraditional plunger which is replaced with that of FIG. 3 in the valve;

FIGS. 9( a) to (d) are plan and sectional profile views of a non-returnvalve according to one embodiment of a second aspect of the presentinvention;

FIGS. 10( a) to (e) are various plan and sectional views of anotherembodiment of this aspect of the invention shown in both open andclosed/pressurised configurations;

FIGS. 11( a) to 12(d) are various underside perspective, sectional andplan views of a variant of the non-return valve of FIG. 15 in its closedand open configurations;

FIGS. 12( a) and 12(b) are part sectional views of a further embodimentof the preceding aspect of the non-return valve in its “neutral” andpressurised configurations;

FIGS. 13( a) and (b) are part sectional views of still anotherembodiment of this aspect of the non-return valve in its “neutral” andpressurised configurations;

FIGS. 14( a) and (b) are sectional views of a pressure relief valve ofan embodiment of a third aspect of the invention shown in its variousworking configurations;

FIGS. 15( a) and (b) are sectional views of a pressure relief valve ofan embodiment of a third aspect of the invention shown in its variousworking configurations;

FIG. 16 shows a sectional view of a pressure relief valve of a furtherembodiment of a fourth aspect of the invention;

FIGS. 17( a) to (c) are perspective plan and sectional views of a highpressure non-return valve according to a fourth aspect of the invention;and

FIGS. 18( a) and (b) are plan and sectional views of a variant of thehigh pressure non-return valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Initially referring to FIGS. 1( a) and (b), a non-return valve and adiaphragm according to preferred embodiments of the first and secondaspects of the present invention are now described. FIG. 1 shows thevalve designated generally as 10 comprising a valve body 12, a diaphragm14, and a valve actuator, in this example being in the form of a plunger16, compression spring 18 and plunger guide tube 20. Though notillustrated, the valve 10 of this embodiment is solenoid-actuated bymeans of an electrically activated magnetic coil which is disposed aboutthe guide tube 20.

The valve body 12 of this example includes a fluid inlet 22 and a fluidoutlet 24 interconnected by a fluid passageway 26. The fluid inlet andoutlet 22 and 24 are defined by threaded and axially aligned portsformed in the valve body 12. The threaded inlet port 22 is formedcontinuous with a transversely directed inlet flow passage 28 which isadjacent and continuous with another transversely directed fluid passage30 which in turn is formed continuous with the outlet port 24. Thetransverse fluid passages 28 and 30 together form the fluid passageway26.

As best shown in FIGS. 2( a) to (e) the other transverse fluid passage30 includes a valve seat 32 which defines a flow aperture 34 in thefluid passageway 26. The valve seat 32 includes a recess 36 in which thediaphragm 14 of this embodiment is seated. The diaphragm 14 as bestshown in FIG. 4 is shaped about its periphery complementary to theperipheral profile of the recess 36. Otherwise, the diaphragm 14includes a conical-shaped portion 38 formed continuous and integral witha flange mounting portion 40. The conical-portion 38 includes one ormore slits 39 formed at an axis of the diaphragm 14 and defining acollapsible aperture therein. The diaphragm 14 of this example isconstructed of a polymeric material in the form of an elastomer such asa rubber material. The diaphragm 14 is otherwise similar in constructionand fabricated according to the teachings of the applicant'sinternational patent application number PCT/AU00/00659. The disclosureof this international patent application together with its equivalentsis to be included herein by way of reference.

As shown in FIGS. 3( a) to (f) the plunger 16 of this embodiment isgenerally cylindrical in shape and includes an axial bore 42. The axialbore 42 is designed to house the compression spring 18 which biases orurges the plunger 16 against the diaphragm 14 and the valve seat 32wherein the valve 10 is closed. The plunger 16 includes a vent aperture44 which serves to balance any pressure differential between the bore 42and the fluid passageway 26. The plunger 16 at a distal end is reducedin diameter and dome-shaped in order to seat against the diaphragm 14.The diaphragm 14, and in particular the annular flange portion 40, thusfunctions as a seal against which the plunger 16 is seated.

The plunger 16 is slidably and axially housed within the guide tube 20of FIGS. 4( a) to (c) and FIGS. 5( a) to (f). The guide tube 20 includesa tubular housing portion 46 formed continuous with a flanged mountingportion 48. The flanged mounting portion 48 includes a circumferentialgroove 50 in which an O-ring 52 is located for sealably mounting theguide tube 20 to the valve body 12. The plunger 16 is actuated by meansof a magnetic coil (not shown) located about the guide tube 20.

The general steps involved in operation of the valve 10 are as follows:

-   -   i) the valve 10 is maintained in the normally-closed by means of        the compression spring 18 which urges the plunger 16 against the        diaphragm 14 for closure of the flow aperture;    -   ii) the diaphragm 14 functions as a non-return valve which        inhibits flow in a reverse direction thus preventing this        reverse flow under, for example, conditions of vibration which        would otherwise result in movement of the plunger 16 from the        valve seat;    -   iii) the valve is activated into an open-position by powering        the magnetic coil which lifts the plunger 16 clear of the        diaphragm 14 and valve seat to allow flow in a forward direction        from the inlet 22 to the outlet 24 whilst the diaphragm 14        prevents any reverse flow of fluid.

In this embodiment the valve 10 is modified from an existing controlvalve which includes the conventional valve body 120 of FIGS. 6( a) to(f) and the plungers 160 of FIGS. 7( a) to (g) and 8(a) to (e). Thetraditional plunger 160 also includes a resilient sealing element 170which seals against the valve seat (now designated) of the traditionalvalve body 120. It has been observed that fluid leakage can occur inthis traditional configuration as a result of wear/deformation of thesealing element 170. The valve body 120 and plunger 160 are replacedwith the valve body 12 and plunger 16 and the diaphragm 14 retrofittedto the modified valve body 12 of the valve 10.

It will be appreciated by those skilled in the art that the valveaccording to the described preferred embodiments has at least thefollowing advantages:

-   -   i) the valve provides effective seating/sealing whilst        minimising the likelihood of flow in a reverse direction;    -   ii) the valve lends itself to maintenance in-situ by means of        the non-return diaphragm without requiring isolation valving;        and    -   iii) the valve and diaphragm lend themselves to retrofitting to        existing installations.

It will be appreciated by those skilled in the art that variations ofthe valves according to the described preferred embodiments arepossible. For example, the diaphragm need not be of the configurationand construction described provided it inhibits flow in a reversedirection. The valve need not be a flow control valve and may extend toa range of duties and fluids including liquids and gases. The valve maybe manually actuated rather than solenoid actuated as described. Thematerial from which the diaphragm is constructed should be resilientlyflexible and may for example be a nylon-base material.

Referring now to FIGS. 9 to 18 valve according to embodiments of thethird and fourth aspects of the present invention are now described.FIG. 9 shows a non-return valve 210 including a detent 211 formedintegral with and extending in an reverse direction from the valvediaphragm 214. The collapsible aperture 222 is formed as a slit whichintersects with the apex of the conical-shaped diaphragm 214 and extendsapproximately midway into the length of the detent 211. The collapsibleslit 222 extends across an annular gap 213 defined between the valvebody 222 and the detent 211. The collapsible slit 222 of this example issubstantially co-planar with an axis of the valve 210 and the detent211.

The non-return valve 210 is moulded from a polymeric material,preferably an elastomer such as rubber or a nylon-based material. Theselection of the appropriate material for the valve 210 if not obviousto one skilled in the art may require a degree of trial andexperimentation.

The valve body 212 includes a pair of opposing step rebates such as 215which are adapted to receive a tool for screw threaded removal orinsertion of the non-return valve 210. In operation, depression of thedetent 211 forces the diaphragm 214 apart and the collapsible slit 222open so as to either purge fluid from the non-return valve 210 or permitthe flow of fluid across the valve 210 in a forward direction. Thedetent 211 provides added rigidity to the diaphragm 214 whilst in useand should be more suited to moulding than the described embodiments ofthe non-return valve.

FIGS. 10 and 11 illustrate a variant of the non-return valve of FIG. 9.In order to avoid repetition and for ease of reference like componentsof this non-return valve as compared to that of FIG. 9 have beendesignated with the same reference numerals. The non-return valves 210of these variants include a thicker walled diaphragm 214 at the annulargap 213 between the valve body 222 and the detent 211. Otherwise, thenon-return valve 210 of FIGS. 9 and 10 are similar in construction andof a single slit 222 configuration. On the other hand, the non-returnvalve of FIG. 11 includes a pair of slits 222 a and 222 b disposed atright angles to one another whilst being co-planar with an axis of thevalve 210. The dual slits 222 a/b of this example permits increased flowof fluid through the valve 210 particularly in its exhausting or purgingcondition.

FIGS. 10( a) and (c) depict the valve 210 in its neutral/closedcondition. In this condition the resilience of the diaphragm 214together with the fluid pressure on the high pressure side of the valve210 effects closure of the collapsible aperture or slit 222. FIG. 10( b)shows the valve 210 in an over pressured condition at around 2000 kPa.The single slit 222 is drawn slightly open in its upper region by thetension exerted by the stressed diaphragm 214. This continued opening ofthe single slit 222 under excessive pressure vents sufficient fluiduntil the pressure returns to normal operating conditions and the valvereverts to its neutral/closed condition illustrated in FIGS. 10( a) and(c). The non-return valve 10 shown in FIGS. 10( d) and (e) is in anopened condition wherein the slit aperture 222 is exposed to permit theflow of fluid from the high pressure side of the valve 210. The slit 222is exposed by depressing the valve actuator or in this example detent 11axially downward toward the high pressure side of the valve 210. Thetension in the diaphragm 214 by depression of the detent 211 urgesopening of the slit aperture 222.

FIGS. 11( a) and (c) are perspective and sectional views of the dualslit variant of the non-return valve 210. The valve 210 is in theserepresentations shown in its neutral/closed condition whereby fluid isprevented from flowing from a high to a low pressure side of the valve210. FIG. 11( d) is an underside plan view of the non-return valve 210in this closed condition wherein the dual slits 222 a/b are sealedtogether under the effect of both the resilient force of the diaphragm214 and the pressure of the fluid on the high pressure side of the valve210. FIG. 11( b) illustrates this dual-slit version of the valve 210 inits open condition wherein the dual slit aperture 222 a/b is exposed topermit the flow of fluid in a reverse direction through the valve. Thedetent 211 is depressed axially toward the high pressure side of thevalve 210 so that the valve 210 assumes this opened condition. It willbe appreciated that the tension in the diaphragm 214 draws the dual slitapertures 222 a/b apart as best represented in FIG. 11( b).

FIGS. 12 and 13 illustrate alternative embodiments of the precedingaspect of the non-return valve 210 including an actuator in the form ofthe detent 211. In these alternative embodiments the detent assembly 211is fabricated separate from the remainder of the valve 210. The detentassembly 211 of FIG. 12 includes an elongate member 215 having at oneend a conical-shaped engaging surface 217 being configured to abut thediaphragm 214 at its inlet side. The detent assembly 211 includes aretaining element or ring 219 fixed to or formed integral with theelongate member 215 and being adapted to engage an annular recess 221formed in an inner wall of the valve body 212. The detent assembly 211is retractably inserted into the valve body 212 prior to, in thisexample, its screw threaded installation. FIG. 12( a) shows thenon-return valve under 0 differential pressure across the valvediaphragm 214 whereas FIG. 12( b) schematically depicts the valve 210with a relatively high pressure of around 1000 kPa exerted on the highpressure side of the valve 210.

FIG. 13 illustrates a non-return valve 210 similar in construction tothat of FIG. 12 but wherein the detent assembly 211 includes theelongate actuator member 215 axially and slidably received within theretaining element 219 which is retractably received within the valvebody 212. In this example the conical-end of the actuator member 215includes a shoulder 223 which abuts the retaining element or ring 219.FIG. 18A shows this variant of the valve 210 with approximately 0differential across the valve diaphragm 214 whereas FIG. 13(B) shows apressurised condition at around 2000 kPa on the high pressure side ofthe valve 210. The retaining ring 19 is designed to deflect under thispressurised condition whilst the diaphragm 214 bears against theconical-shaped engaging surface 217 of the detent assembly 211.

FIG. 14 depicts various sectional views of a pressure relief valve 210according to another aspect of the invention. For example, such apressure release valve may be used to release excessive pressure andthereby prevent destyruction. The pressure relief valve is essentiallylow profile or squat and a heavy walled version of the previouslydescribed non-return valve. Similar components/features of this pressurerelief valve 210 have been designated with the same reference numeral asthe corresponding feature of the non-return valve. The pressure reliefvalve 210 of FIGS. 14( a) and (b) is of a single slit configurationwhereas the valve 210 of FIGS. 15( a) and (b) are fabricated in a dualslit configuration. FIGS. 14( a) and (b) show the pressure relief valves210 in a relaxed condition at zero differential pressure across thediaphragm whereas FIGS. 15( a) and (b) depict the valve 10 venting at anexcess pressure of around 440 kPa. The pressure relief valve 210 isdesigned so that an axial deflection of the diaphragm 214 toward theinlet side of the valve 210 effects partial exposure of the collapsibleslits 222 to vent excessive pressure on the high pressure side of thevalve 210. The resilient forces exerted by the conical-shaped diaphragm214 thereafter draws the diaphragm 214 towards its passive or neutralcondition as depicted in FIGS. 14( a) and 15(a). The pressure reliefvalve 210 can thus be designed, for example by material selection and/orconfiguration of the conical diaphragm, to vent or release pressure at apredetermined value.

FIG. 16 shows a spray nozzle assembly 230 that includes a pressurerelease valve 231. The assembly may, for example be used for irrigationpurposes. The assembly 230 comprises a fluid passage way 232 having aninlet 233 and a nozzle 234 which provides a fluid outlet. Above apredetermined fluid pressure in the passage way 232, the valve 231 opensand fluid flows through the passage way 232, through the filter 235 andexits through the nozzle 234. In this assembly the valve 231 comprises adiaphragm that is oriented in a reverse direction and towards the lowpressure region. The usage of the pressure release valve 231 relates tosignificant practical advantages as the number of moveable parts it theassembly 230 is significantly reduced compared with irrigationassemblies known in the art. Therefore, production costs may be reduced.Further, the simplicity of the valve also reduces the likelihood ofresidue built up which is a known problem in the art, in particular ifthe fluid comprises solutes.

FIG. 17 shows a high pressure non-return valve 210 according to yetanother aspect of the invention. The non-return valve 210 of thisembodiment is configured for relatively high pressure applications suchas those exceeding 400 kPa, for example this valve 210 has applicationin a sports ball. The valve 210 is still of the same generalconstruction as that of the previous embodiments except that it isrelatively squat in sectional profile and includes a relatively smalldiameter fluid passageway 216. The ball valve 210 of this exampleincludes a conical-shaped diaphragm 214 of a dual slit 222 a/bconfiguration. The applicant conducted pressure testing on a prototypeof the high pressure non-return valve 210. In these tests the valve 210maintained a pressure of 425 kPa for 1100 hours. These actual tests wereconsistent with and validated data obtained from computational modellingperformed on a corresponding valve.

FIG. 18 depicts a high pressure non-return valve which is similar inconstruction to the pressure relief valve 210 of FIGS. 14 and 15 exceptthat it is not designed for venting. The non-return valve 210 is of thedual slit 222 a/b configuration and includes a reinforcing member in theform of a conical-shaped cage 225. The cage 225 is shaped generallycomplementary to an inlet side of the diaphragm 214 and is press-fitwithin the valve body 12 on an inlet side of the diaphragm 214. Thereinforcing member or cage 225 includes an innermost ring-shaped memberconnected to a series of larger diameter and coaxially disposed ringmembers via radially extending spokes. The innermost ring member issized to permit the passage of a nozzle or the like for purging orfilling via the valve 210. The reinforcing member 225 is designed tosupport the valve diaphragm 214 so that increased pressure can beapplied to its high pressure side without inversion of the diaphragm214. Very high relative pressure may be required to open the valve andpermit pressure release. In all embodiments the diaphragm may alsofunction as a seal and seal the valve body. This has the advantage thatbecause of this secondary function of the diaphragm an o-ring seal maybe replaced which simplifies the design.

Components of the valve 210 including the diaphragm can be manufacturedby injection moulding and reference is made to international patentapplication WO 00/77429.

Now that valves according to preferred embodiments of the third andfourth aspects of the present invention have been described, it will beapparent to those skilled in the art that the non-return valve, pressurerelief valve and permeable membrane have at least the followingadvantages:

-   -   i) the non-return and pressure relief valves are relatively        simple in construction;    -   ii) the non-return valve is effective in operation relying on        fluid pressure for opening, and valve membrane characteristics        and design for closure; and    -   iii) the non-return and pressure relief valves are relatively        inexpensive to manufacture.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. For example, injection moulding is merely oneexemplary technique of forming the non-return valves. The diaphragm maybe constructed of practically any resiliently flexible material which ina collapsed condition obstructs the collapsible aperture to prevent flowacross the valve or membrane. The non-return valves may extend toapplications other than those described above. For example, thefail-safe non-return valve may be connected across the skin of a ship'shull and provide a means of quick evacuation where the human body canslip through dual or multiple diaphragm valves.

All such variations and modifications are to be considered within thescope of the present invention the nature of which is to be determinedfrom the foregoing description.

It is to be understood that, the international patent application WO00/77429 to which reference is made does not constitute an admissionthat this international application forms a part of the common generalknowledge in the art, in Australia or any other country.

1. A valve comprising: a valve body having an inlet opening and anoutlet opening interconnected by a fluid passageway having a flowaperture; a diaphragm being constructed of a resiliently flexiblematerial and located across the flow aperture and including acollapsible aperture which inhibits flow from the outlet to the inletopenings via the flow aperture in a reverse flow direction; and a valveactuator for influencing the flow from the inlet to the outlet, thevalve actuator comprising a plunger together with a compression springwhich urges the plunger into sealed abutment with the diaphragm.
 2. Thevalve as claimed in claim 1 wherein the diaphragm is disposed about theflow aperture and the valve actuator is at least in part movably coupledto the valve body and arranged to operatively cooperate with thediaphragm to effect closure of the flow aperture to prevent flow fromthe inlet to the outlet openings in a forward flow direction.
 3. Thevalve as claimed in claim 1 wherein the plunger is elongate andconfigured at one end to abut the valve diaphragm which is seated aboutthe valve seat.
 4. The valve as claimed in claim 1 comprising a plungerguide tube in which the plunger is slidably housed for reciprocatingmovement.
 5. The valve as claimed in claim 4 comprising a solenoidactuator which is located about the plunger guide tube and whenelectrically activated is designed to effect axial movement of theplunger out of abutment with the diaphragm to permit flow in the forwardflow direction.
 6. The valve as claimed in claim 2 wherein the diaphragmis shaped about its periphery substantially complementary to a recessformed around the flow aperture, the recess being for seating of thediaphragm relative to the flow aperture.
 7. The valve as claimed inclaim 6 wherein the diaphragm is fixed or adhered into the recess. 8.The valve as claimed in claim 1 wherein the diaphragm is designed toretrofit to the valve.
 9. The valve as claimed in claim 1 wherein thevalve is a flow control valve.
 10. The valve as claimed in claim 1wherein the valve actuator is connected to the diaphragm and isconfigured so that axial movement of the actuator toward the fluidoutlet deflects the diaphragm to expose the aperture and allow fluid toflow through the passageway from the inlet to the outlet or the otherway.
 11. The valve as claimed in claim 1 wherein the diaphragm is in theform of a generally conical-shaped diaphragm having the collapsibleaperture located at or adjacent its apex which is orientated in theforward flow direction.
 12. The valve as claimed in claim 1 wherein thecollapsible aperture is in the form of one or more slits each beingformed through an axis of the valve.
 13. The valve as claimed in claim 1being constructed of a resiliently flexible polymeric material.
 14. Thevalve as claimed in claim 13 wherein the polymeric material is anelastomer.
 15. The valve as claimed in claim 14 wherein the elastomer isa rubber material.
 16. The valve as claimed in claim 13 wherein thepolymeric material is a nylon-based material.
 17. The valve as claimedin claim 1 wherein the diaphragm also has a sealing function.
 18. Avalve comprising: a valve body having an inlet opening and an outletopening interconnected by a fluid passageway having a flow aperture; adiaphragm being constructed of a resiliently flexible material andlocated across the flow aperture and including a collapsible aperturewhich inhibits flow from the outlet to the inlet openings via the flowaperture in a reverse flow direction; and a valve actuator forinfluencing the flow from the inlet to the outlet, the valve actuatorcomprising an elongate member formed integrally and generally coaxialwith the valve diaphragm and being configured so that axial movement ofthe actuator toward the fluid outlet deflects the diaphragm to exposethe aperture and allow fluid to flow through the passageway.
 19. Thevalve as claimed in claim 10 wherein the collapsible aperture is in theform of one or more slits each being formed through an axis of the valveand the valve diaphragm is formed integrally with the valve body. 20.The valve as claimed in claim 10 wherein the valve body is configured toretrofit to an existing valve stem.
 21. The valve as claimed in claim 10wherein the valve body is designed to be sealably inserted into a flowline.
 22. A high pressure non-return valve comprising: a valve bodyincluding a fluid passageway which defines a fluid inlet and a fluidoutlet located on a low pressure and high pressure side of the valverespectively; a valve diaphragm being connected across the fluidpassageway and including a collapsible aperture, said diaphragm beingconstructed of a resiliently flexible material and being configured sothat pressure imposed on the high pressure side of the valve promotesclosure of the collapsible aperture to prevent fluid flowing in areverse direction toward the inlet; and a reinforcing member beingdisposed across the valve body and designed to operatively engage thediaphragm on its low pressure side whereby the reinforcing memberrestricts deflection of the diaphragm when a relatively high pressure isapplied on the high pressure side of the diaphragm thus maintainingclosure of the collapsible aperture and the valve.
 23. The high pressurerelease valve as claimed in claim 22 wherein the valve diaphragm isgenerally conical-shaped having its apex directed to the outlet and thehigh pressure side of the valve.
 24. The high pressure release valve asclaimed in claim 22 wherein the reinforcing member is conical-shaped andconfigured to nest within the fluid passageway adjacent the diaphragm onits inlet side.
 25. The high pressure release valve as claimed in claim24 wherein the conical-shaped member comprises a plurality of fluidopenings to permit the passage of fluid.